Arms for the distribution of concrete are known, mounted on heavy work vehicles used in the building sector, consisting of a plurality of segments which allow them to reach the greatest lengths and distances.
Some segments of the known type, as described in the European patent application EP-08152672.5 in the name of the present Applicant, are at least partly made of composite material which, given the same extension reached with respect to a traditional arm made of metal material, allow an overall reduction in the weight of the arm. This because composite material has good resistance and rigidity, to which can be added a greater lightness.
Such segments normally have a rectangular section which narrows substantially continuously along its whole extension. The segments can also comprise longitudinal or transverse stiffening and/or connection elements, made of metal or composite material, which connect to specific elements which are glued or drowned in the structure of the main beam directly during the production step of the segment.
Based on the idea of using composite material to construct the articulated arm, the European patent application EP-08164624.2, also in the name of the present Applicant, shows a possible construction technique of such an arm, which aims to reduce its production costs, guaranteeing a greater flexibility and versatility of manufacturing.
According to this technique segments of articulated arms are made, in which the sizes of the transverse section of the segment are constant along its whole extension.
The segments are formed by depositing a predefined plurality of layers of composite material subsequently subjected to polymerization.
The forming mold used advantageously consists of a plurality of elementary molds of constant section, connected to each other in sequence, for example flanged, and in the number desired to obtain the desired length.
The molds, which are all identical to each other, can be made starting from the same model, with obvious savings.
This solution allows to obtain a constant section on the whole length of the segment and therefore does not allow to reproduce the traditional concept of reduction of the section over the length of the segment.
One purpose of the present invention is to obtain significant reductions in production costs, in particular in the design and construction of the relative molds and models, and to allow maximum flexibility and versatility in production for assembly on different types of vehicles depending on the specific requirements, as well as to allow to obtain a section which varies over its length.
Another purpose is to allow great flexibility in the choice of length, resistance and rigidity of the segments of the arm, allowing to vary on each occasion one and/or the other of said parameters depending on the specific needs and requirements.
A further purpose is to optimize the distribution of the composite material along the extension of the segment depending on the stresses to which it is subjected, in this way obtaining an optimum compromise between mechanical resistance of the segment and distribution of the polymeric material along the whole extension of the segment.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.